There is a known array antenna apparatus in which a plurality of antenna elements are arranged for performing at least one of transmission and reception of electromagnetic waves such as a microwave and a millimeter wave (see PTD 1 to PTD 3).
PTD 1 discloses an array antenna apparatus in which a plurality of antenna modules are mounted on a printed circuit board. Each of the plurality of antenna modules includes: a stacked substrate of multilayer ceramic provided with a patch antenna; and an electric element disposed in a cavity provided in the stacked substrate of multilayer ceramic.
PTD 2 discloses an array antenna apparatus configured by joining: one semi-insulating gallium arsenide substrate (semi-insulating GaAs substrate) having a plurality of antenna conductors and active element circuits; and one silicon substrate (Si substrate) including a plurality of signal processing circuits.
PTD 3 discloses an array antenna apparatus configured by stacking: one first dielectric substrate having a plurality of parasitic elements formed thereon; one second dielectric substrate having a plurality of radiation elements formed thereon; and one third dielectric substrate having a plurality of phase shifters formed thereon.